Control mechanism for disabling respotter upon either the downing of a selected pin or the rolling of a gutter ball



March 8, 1966 M, SANDERS ET AL 3,239,222

CONTROL MECHANISM FOR DISABLING RESPOTTER UPON EITHER THE DOWNNG OF ASELECTED PIN OR THE ROLLING OF' A GUTTER BALL Criginal Filed April 4,1957 7 Sheets-Sheet l 3,239,222 HER THE M` SANDERS ET AL ECHANISM FORDISABLING RESPOTTER UPON EIT F March 8, 1966 '7 Sheets-Sheet 2 CONTROL MDOWNING O A SELECTED FIN OR THE ROLLING OF A GUTTER BALL Original FiledApril 4, 1957 vvvvvvv vvvvvvv Annu vvvvvvv INVENTORS. #Ol/V490 S. AM/V/ll//l/ .SAA/056 BY Mama 2 04.1....

March 8, 1966 M, SANDERS ET AL 3,239,222

CONTROL MECHANISM FOR DISABLING RESPOTTER UPON EITHER THE DOWNTNG OF ASELECTED PIN OR THE ROLLING OF A GUTTER BALL Original Filed April 4,1957 '7 Sheets-Sheet 5 3,239,222 CONTROL MECHANISM FOR DISABLINGRESPOTTER UPON EITHER THE DOWNING OF A SELECTED Original Filed April 4,1957 March 8, 1966 M. SANDERS ETAL DIN OR THE ROLLING OF A GUTTER BALL'7 Sheets-Sheet 4 March 8, 1966 M SANDERS ET AL 3,239,222

CONTROL MEOHANISM FOR DISABLING RESPOTTER UPON EITHER THE DOWNING OF ASELECTED PIN OR THE ROLLING OE A GUTTER BALL Original Filed April 4,1957 7 Sheets-Sheet 5 w u EN les Ng E@ e lu E t Ng x* E En@ .A A lll m ff:

EINE lll rra/@NIK M. SANDERS ET AL 3,239,222

N EITHER THE IN OR THE ROLLING OF A GUTTER BALL March 8, 1966 7Sheets-Sheet 6 CONTROL MECHANISM FOR DISABLING RESPOTTER UPO DOWNING OFA SELECTED l Original Filed April 4, 1957 INVENTOR. #0x/mea s. Ame/v/v//A 70A/ SAA/@fes fnmu U2. @vim Y .SMN

,4 frog/Vix March 8, 1966 M. SANDERS ET Al. 3,239,222

CONTROL MECHANISM FOR DISABLING RESPOTTER UPON EITHER THE DOWNING OF ASELECTED PIN OR THE ROLLING OF A GUTTER BALL Original Filed April 4,1957 '7 Sheets-Sheet 7 l/Y6. I4,

"ssa" PEESE'A/CE EFL A V3 BALL CHANNEL S United States Patent C CUNTRULMECHANISM FOR DISABLING RESPOT- TER lUPN EITHER THE DOWNING F A SELECTEDPIN 0R THE ROLLING 0F A GUTTER BALL Milton Sanders and Howard S.Halpern, Stamford, Conn., assignors to American Machine & FoundryCompany, a corporation of New Jersey Application Mar. 24, 1960, Ser. No.17,283, now Patent No. 3,169,765, dated Feb. 16, 1965, which is adivision of application Ser. No. 650,634, Apr. 4, 1957, now Patent No.2,980,424, dated Apr. 18, 1961. Divided and this application June 12,1964, Ser. No. 374,854

3 Claims. (Cl. 273-43) This application is a division of our copendingapplication Serial No. 17,283, filed March 24, 1960, now Patent No.3,169,765, which is a division of application Serial No. 650,634, filedApril 4, 1957, now Patent No. 2,980,424.

This invention relates to bowling pin-setting machines and moreparticularly to completely automatic bowling pin-setting machines inwhich the operations are electrically controlled in accordance withconditions arising in the course of playing of the bowling games. Moreparticularly the invention relates to an automatic control of a timedelay of a pinspotter by detecting pins in motion, thus shortening theaverage pinspotter cycle by having time delays of the pinspottervariable rather than fixed at the maximum expected duration of pinmotion, which is the case in the presently used pinspotters. Theinvention `also includes novel pin fall detecting and signallingmechanism, which indicates the pin fall results after each ball of aframe is rolled. The invention also discloses a control system whichprevents the normal, cyclic operation of the machine, and moreparticularly, the prevention of the operation of its pin-setting andresetting mechanism, when only pin #7 or pin #10 is knocked olf the pindeck of the alley only by the rst ball without knocking down any otherpins, and allowing the normal operation of the machine if either pin #7or I# 10 is knocked out by the second ball in any given trame. Knockingdown of either pin #7 or pin #10 by the second ball, without knockingdown any additional pins, can take place only when the rst ball is agutter ball which leaves all pins standing for the second ball, androlling of the second then knocks out only pin `#7 or #10. Under suchconditions playing of the frame has been cornpleted and, therefore, thedisclosed system permits the normal operation of the pin-settingmechanism. In bowling pin setting machines, one of the main problems isto make all operations as quickly as possible, and to make theseoperations comply with the rules of the American Bowling Congress. Someautomatic bowling machines now in use have a standard delay time foroperating pin setting machines to prevent the operation of the machinewhile any of the pins are in motion. This delay time, as a rule, isequal to the maximum pin motion time that may be encountered in anyplay. However, there is a much larger number of plays which do notproduce any pin motion, such as pin wobble, and, therefore, the maximumdelay time built into the present machines is wasteful of time. Thismaximum delay time, as a rule, is derived from the maximum duration of apin wobble that can take place without producing a pin fall. The pinwobble may be defined as an oscillation of a bowling pin around itsvertical axis. This oscillation may be compared with an oscillation of apendulum, except that while in the pendulum the center of gravity isbelow the point of pendulum suspension, in the pin wobble;t the centerof gravity of the pin is above the point of suspension which, in thiscase, is the alley oor supporting rice the pin. The pin wobble, as arule, therefore, is in a single vertical plane with the pin rstdetiecting to one side and then to the other from its normal verticalposition. The energy involved in pin wobble cannot exceed that required.to tilt the pin from its normal upright position of stable equilibriumwhich is reached when the center of gravity of the pin is directly abovethe point of contact of the pin with the alley floor. If more energy issupplied to the pin than that required to tilt it to its condition ofunstable equilibrium, the pin will fall over directly and not wobble. Asthe pin base becomes worn with use, the base edge becomes more roundedand the point of contact of the pin with the alley floor comes closer tothe laxis of symmetry of the pin. The position of unstable equilibriumis reached with a smaller tilt with the old pins, having worn out bases,than with the new pins. For a new pin, the maximum duration of pinwobble is about nine seconds and the maximum peak-to-peak motion of thepin head is about ve inches. The fixed delay built into the pinspottersis less than nine seconds because it is unnecessary to hold up theoperation of the machine all full nine seconds even if the maximumpossible amplitude wobble does occur. If the pin does not fall withinthe rst maximum amplitude, it, obviously, will not fall as theamplitudes diminish. However, the operation of the machine cannot bestarted until the amplitude has died down sufficiently so as to produceproper engagement of the pin and the pinsensing and respotting cups andavoid knocking down of the wobbling pin by premature lowering of therespotting cup. Moreover, the players do not wish to see the pinspottergo into operation until all wobble ceases, and the latter consideration,which is of purely psychological nature, requires the xed time delay tobe much longer than that required by the pin wobble itself. Usually thisxed time delay is of the order of 6 to 7 seconds. Since by far thelarger number of plays do not produce any pin wobble, the operation ofthe pinspotter can be expedited considerably by making the time delayequal to zero when there is no wobble and variable when there is wobble,the actual duration of any specific delay being controlled by the wobbleitself so that the delay is very short when there is only a slightwobble and longer when the wobble is more pronounced.

There are also present, at times, such pin motions as pin spin and pinroll. The path of the rolling pin is approximately an arc of a circleand the pin spin usually is transformed into a pin roll after thespinning pin loses some of its energy. The duration of pin roll islimited by the dimensions of the alley floor and the presence of otherpins. The pin roll and. pin spin cease in less time than that requiredfor pin wobble to cease. Therefore, the duration of pin wobble ratherthan that of pin roll or pin spin, determines the maximum delaynecessary in pinspotter operation.

In order to increase the intelligence of the detecting system stillfurther it is also necessary for such detection system to provide a pinpresence signal in addition to the pin wobble signal. With the pinwobble and presence signal made available by the detecting system, thefollowing improvements in the operating cycle of the pinspotter becomepossible:

(1) Variable time delay for putting pinspotter into operation, this timedelay being controlled directly by pin wobble so that this time delay ismade equal to zero when there is no pin wobble.

(2) Elimination of sweep and table operation when only pin #7 or pin #10is knocked out into pit by the rst ball.

(3) Elimination of sweep and table operation when the first ball is agutter ball, and when both balls are gutter balls.

(4) Direct operation of the pinfall signal means by the detectionsystem. v

The disclosed systems, described briefly, are ,as follows: One of thesimplest systems is the system based upon amplitude modulation of theecho by a pin which is in motion. The simplest version of such system isthe one using light as transmitters and photo cells as receivers.Amplitude modulation by pin wobble of the lig-ht reflected from a movingp-in into the photo cell is such a system. A system yof pin-hole lensesfocus an image of the pin tops in the plane of patterned mask. Thepatterned masks (a grid having alternating transparent andnon-transparent patterns) are so arranged that the transmittedillumination is a function of pin position with respect to therespective mask with a uniform light field illuminating the pins. Thelight transmitted through the mask is focused on a photo cell whoseiout-put will have a varying component cor-responding to pin wobble. Ifonly one photo cell is used for -all ten pins, Le., all ten pin images.are focused on a single photo cathode, the resulting system willproduce -a wobble-and-presence detector which will not indicate thepresence or .absence of any individual pins. Individual pin wobble andpresence is obtained by using a separate pin-hole lens and a separatephoto cell to examine the image of each pin.

The .additional versions :of the systems all utilize an electro-magneticphenomena for producing an electrical signal in response to a wobble andpresence. Variations in the electro-magnetic or electrostatic fieldsimbalance electrical circuits to produce a modulated alternating currentwave corresponding to wobble and a variable amplitude signal, or lachange in the level of the signal to indicate pin presence. Thesesignals, in turn, are used in the same manner as the signals from thephoto-cathodes, for producing the desired effects in the relay systemused for initiating the operating cycle fof the pinspotter.

It should -be stressed at .this point that whatever the detecting systemis, it must be capable of producing two types of signals, one forindicating wobble, and the other -and different type of signal-forindicating presence. These two types of signals are first produced in acommon transducer and they are then separated from each other anddirected to two separate control channels. The wobble signals controlthe operation of the wobble signal channel, and the presence signalscontrol the operation of the presence signal channel. In the purelyelectrical detection systems, the transducer produces a modulatedalternating current wave in response to wobble, and a change in thelevel, or amplitude, of the same alternating current wave in response tothe absence of a pin. In order to have a clearer understanding of theterms modulated wave and change in level, it may be helpful to say thatthe modulated wave signal is produced by using a pin wobble as a meansfor modulating a normally constant amplitude alternating currentproduced by some suitable source, such as a crystal-controlledoscillator. The degree of modulation is a function of the amplitude ofthe wobble; the larger is the wobble, the larger is the modulation. Thepresence of a pin, on the other hand, produces a constant amplitudesignal having a constant amplitude a when the pin is present, and aconstant amplitude b when the pin is absent with a being greater orsmaller than b. The wobble signal, produced by the above class ofsystems, shall be called as the amplitude -modulated signal, or the A.M.signal to correspond to the well-known, and identical amplitudemodulation used in radio, television and other forms of A.M.communication systems, as differentiated from F.M., or frequencymodulation systems. The presence signal shall be called the levelmodulation signal (LM.) for lack of a better term. In the above term,the word modulation means the change in the level of the signal whichtakes place when the pin is removed from its normal standing position,i.e., knocked down.

This change in level takes place at the moment the pin is knocked down.

When the transducer is an optical transducer, two types of signals, A.M.and L M. are also produced but the carrier wave is a direct currentcarrier as differentiated from the alternating current carrier. Sincedirect current ampliers are less stable than alternating currentamplifiers, the A.M. and L M. signals in the above type of system may betransformed in the electronic detection channels into A.M. and L M.si-gnals having an alternating current carrier for eliminating the useof direct current amplifiers.

It is therefore an object of this invention to provide a pin presencedetection system.

It is an additional object of this invention to provide a purelyelectrical pin presence detection system.

A further object of the invention is to provide a novel pin falldetecting device wherein pin fall is detected after each ball of a frameis rolled without the use of physical means being moved relative to abowling alley to detect the presence or absence of standing pins on abowling alley.

It is a further object of the invention to provide a pin fall detectingand signalling mechanism for use with a bowling Ipin for use with abowling alley wherein there is generated a signal in the detectingsystem in response to the knocking down of a pin or pins normallystanding on the pin spotting bed of a bowling alley.

It is an additional object of this invention to provide an improvedelectrically controlled automatic bowling pin-setting machine having acontrol system capable of responding to and controlling the time ofoperation of the machine and preventing its operation when only pin #7or pin #10 is knocked down by the first ball when all pins are presentafter ball #l or ball #2 are rolled without knocking over any pins,which are known as gutter balls.

It is a further object of this invention to provide an improved controlsystem for an automatic bowling pin setting machine, the control systemhaving electrically controlled means responsive to the presence andabsence of pins after an impact of a ball on the bowling pins, andhaving a relay system capable of timing the operation of the machine inresponse .to pin presence signals.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description taken in connection with the accompanyingdrawings in which several embodiments of the invention are illustratedas examples of the invention. It is to be expressly understood, however,that the drawings are for the purpose of illustration and descriptiononly, and are not intended as a definition of the elements of theinvention. Referring to the drawings:

FIGURE 1 is a block diagram of a wobble and presence detection system;

FIGURE 2 is a block diagram of an optical wobbleand-presence detectionsystem;

FIGURE 3 is a front elevational view of the camera used in connectionwith the system illustrated in FIG- URE 2;

FIGURE 4 is a plan view of the viewing mask for the camera illustratedin FIGURES 2 and 3;

FIGURE 5 is a schematic diagram of the electronic channel of FIGURE 2;

FIGURE 6 is a block diagram of an inductance pin wobble and pin presencedetector system;

FIGURE 7 is the modified version of the inductance pin wobble and pinpresence detector system disclosed in FIGURE 6;

FIGURE 8 is a schematic diagram of the isolating detector used in thedetection system disclosed in FIG-I URE 7;

FIGURE 9 is a block diagram of a detection system using a bridgecircuit;

FIGURE 10 is partly a schematic diagram and partly a block diagram ofthe detection system using an inductance bridge;

FIGURE 11 is a side view of a pin and flow coil used in conjunction withFIGURE 10;

FIGURE 12 is partly a schematic diagram and partly a block `diagram oflthe detection `sys-tem using a capacitance bridge;

FIGURE 13 is a side view of a pin and capacitor mounted on the floorused in conjunction with FIG- URE 12;

FIGURE 14 is a schematic diagram of the relay system operated by thedetecting systems;

FIGURES 15 and 16 illustrate a suitable type of gutter ball detectingmechanism.

Basic components of the detection system Referring to FIGURE 1, itdiscloses a simplified block diagram of a pin wobble and presence systemfor a single pin 2. When reflected light is used for detecting thewobble and presence of the pin, the pin needs no modifications of anykind. The light reflected by the pin produces the amplitude modulatedlight signal when the pin wobbles, and it produces the level modulatedlight signal when the pin is absent. These light signals are convertedinto the corresponding electrical signals by the detection system 3. Theamplitude modulated signals (A.M.) are then separated from the levelmodulation presence signals in the detection system 12 and are impressedon a condenser 4 while the level modulation signals are impressed on aconductor 5. These two signals are then used to control the operation ofa pinsetter in the manner pointed out in the introductory part of thespecification.

When the detection system 3 is all electrical, or electronic system, astandard pin, without any additional modifications within the pinitself, may be used when a capactive coupling between the base of thepin and a capacitor mounted in the alley floor is used for convertingpin wobble and pin presence directly into the A.M. and LM. electricalsignals. When the capacitive effect is replaced with the inductiveeffect, it is preferable to mount a small coil at the base of thebowling pins for increasing the useful magnitude of wobble and presencesignals. The bowling pins of the above type are described more in detailin the copending US. application for patent of Milton Sanders havingSerial Number 615,736, filed on October 11, 1956, now Patent No.2,973,206, and entitled Bowling Pin.

The above detection systems are described more in detail below,beginning with the description of the opticoelectronic system.

Optico-electronic detection system` The block diagram of this system isshown in FIG- URE 2, the transducer, including a pin-hole camera 10, ispartly shown in FIGURES 3 and 4, and the schematic diagram of thedetecting and signal-separating circuits is shown in FIGURE 5.Accordingly, this system will be described in connection with FIGURES 2through 5. The transducer, per se, which transforms mechanical movementof the pins, such as wobble and presenceabsence, includes a source oflight 30, pins 12, a pin-hole camera 10, and a mask 24 mounted withinthe camera. This optical transducer converts the pin wobble into anamplitude-modulated light signal and pin presence into a level modulatedlight signal. These light signals are focused on the photo-cathode 52 ofa photo-cathode multiplier 50, FIGURE 5, where the light signals areconverted into electrical signals and the electrical signals are thenused for controlling the operation of the pinspotter machine. FIGURES lthrough 5 illustrate only one optico-electrical detection channel forone pin;

the overall system includes ten identical individual channels of theabove type, one channel for each pin. Each channel furnishes informationconcerning the status of its pin in terms of wobble and presence andthese signals are used for controlling the operation of the pinspotter.Only one wobble-and-presence channel is illustrated for simplifying thedescription and drawings.

Referring to FIGURE 2., it illustrates the relative .position of camera10 with respect to the alley iioor 11 and pins 12. The most advantageouslocation for camera 1t) is on an alley mask 13 directly behind thepinfall signal means 14. Camera 1t? for pin #l is in a vertical planepassing through the central, longitudinal axis of the alley, `and theremaining cameras are positioned to the left .and right of this camera.The cameras for the back row pins (7 through 10) are placed above theiirst row of cameras. Such positioning of the cameras producesreasonably uniform in .size images of the pins, in the respectivecameras, making the signals from the various pins more nearly uniform.The cameras, thus mounted, will not be subjected to vibrations as theywould be i-f mounted on the machine. An additional advantage of suchmounting is that the camera is very unlikely to be hit by ying pins inthis location.

Referring now to FIGURE 3, it illustrates the front View of the camera.It is mounted in a box 1S having two identical front plates 16 and 17.Plate 16 is provided with a single pin-hole 18, while plate 17 is-provided with three pin-holes 19 through 21. The pinhole plates 16 and17 constitute the front ends, or faces, of two independent cameras, onecamera, with plate 16 and pin-hole 18 being used to focus the image ofthe upper portion (the upper rounded end) of some particular pin on amask 24, FIGURE 4, while plate 1'7 and pin-holes 19, 2t) and 21 are usedfor focusing the general background alley illumination on theph-otocathode used -for compensating the detector against any uctuationsin this illumination. Mask 24 is mounted on a metallic bracket (notshown) which supports the mask approximately three quarters off an inchbehind the pinhole plate 16. Only one mask is used in one of thecameras, such as camera 16 which is used for detecting pin wobble andpin presence. The illumination compensating camera 1'7 does not requirethe use of `any mask. Mask, or grid, 24 is made of transparent basematerial, such as glass or cellulose acetate film, with anon-transparent grid pattern 25 superimposed on the transparent base.The preferred version of the Agrid pattern, which was found to producemaximum amplitude variations, consists of a saw-tooth wave 26,projecting beyond the straight strips. It has been found experimentallythat such pattern produces the most uniform amplitude signal from allthe pins located in various positions, and no pin in the field of viewof the camera and the grid can mofve in any manner without a change inthe intensity of the light transmitted through the mask. T'hus there isno problem of orientation o-f the mask with respect to the pin images.The widths of the opaque strips, clear strips and saw-tooth edge areequal to each other. The Sawtooth angle is 45. The function of thesawtooth edge on the mask is to increase the signal produced by theforeshortening of the pin image as a pin wobbles back and forth towardand away from the camera. Versions of this mask with various scalefactors are not critical as long as the mask is no-t so coarse as topermit a pin to wobble without part of its image moving out from behindan opaque strip into the sawtooth, or clear area, and not so tine as t0lose signal strength. The marks are .also scaled so that the width ofthe opaque strips at their narrowest points is -made equal to the widthof the incident image of the pin neck. In the illustrated version of themask, the indicated dimensions 51, b and c :are equal to each other. Itis to be understood that this invention is not restricted to theabove-mentioned configuration of the mask, and other patterns can beused successfully so long as the above basic considerations are kept inmind.

The pinhole camera 10, illustrated in FIGURE 2, uses a pinhole in eachcamera for detecting the pin wobble and presence. A pinhole lens,sufficiently small to resolve the head of a bowling -pin (in one examplethe pin holes were .03 inch in diameter), admits sufiicient amount oflight to permit operation of the detector with a reasonably simple andinexpensive photomultiplier circuitry. A pinhole lens is simply a hole,of a proper size and placement, drilled in la sheet of opaque material.The pinhole lens, in addition to its obvious advantage of low cost, alsohas a wide angle and provides an image of clarity, relativelyindependent of object distance because of an infinite depth of focus;thus the pinhole lens can be focused on the king pin or on the rear pin,and its field of view may be controlled by varying the distance betweenthe pin hole and the photo-cathode. Three pinholes are used in camera 17illustrated in FIGURE 3 in order to obtain a better integration of theoverall back-ground illumination.

The sensitivity of the photomultiplier tube is not uniform over thecathode surface, but is highest in the central region and drops rapidlytoward the edges of the cathode. This is probably due to a highermultiplication being obtained with electrons leaving the central.portion of the cathode than from those leaving the cathode edges. Inorder to obtain a reasonably good signal informity from all the pins,all individual pin cameras should focus the pin heads on the centralportion of the photo-cathode.

All of the components of the detector and the source of illumination 30are energized from all alternating current source, which is used forproviding electrical energy for `actuating all the detectors, the lightsand the motors used in connection with pins-etters. Whenever a suddenload is connected to the source, it is apt to produce either transientsor variations in the magnitude of such voltage, or both, which are aptto influence proper operation of the detectors. In order to cancel theeffect of such transients and fluctuations in the intensity ofillumination, the detector is provided with the compensating viewinghead, or camera 17, illustrated in FIG- URE 3, which is identical to theviewing, or camera 16, used for producing the wobble signal except thatit has three pinholes 19-21 and no mask. A photomultiplier is alsomounted in the back of the viewing head 17 to convert the light passingthrough the pinholes into an electrical signal which compensates for anyvoltage lluetuations. Accordingly, head 17 produces a signal which isproportional to the intensity of illumination, but it is nonresponsiveto the wobble, rolling or spinning of the pins. In view of the absenceof mask 24 in head 17, some difference in the overall intensity ofillumination will generally occur when some of the pins are spinning orrolling and such signal, as a rule, will also be converted into anelectrical signal. These signals have a .sufiiciently low amplitude and,therefore, do not affect the operation of the pin setting machine.

The outputs of the two photomultipliers are connected to a differencecircuit 32, the output of which produces a wobble signal and a presencesignal. These signals are used for timing the operation of thepinsetter. The effect of light intensity fluctuations, therefore, issubstantially cancelled out because both cameras are equally affected'by the random fluctuations in the intensity due to voltagefluctuations. The photomultiplier load resistors are adjusted toequalize the anode voltages in the two viewers, with all pins standing.Complete compensation of light changes occurs only when all pins arestanding. However, the useful signal has a sufficiently large amplitudefor practical purposes.

In order to minimize the effect of the line voltage on the entiredetector still further, it is desirable to use a regular voltage supplywhich uses voltage regulator gas lled tubes. Such regulated voltagesupplies are well known in the art and, therefore, need no furtherdescription.

The output of the difference circuit 32 produces two signals: One signalis the amplitude modulated signal corresponding to the pin wobble, andthe second signal is the level modulated signal corresponding to pinpresence and absence. These are the previously mentioned A.M. and L M.signals. The two signals are both impressed on a presence amplifier 33where the wobble signal is filtered out so that only the L.M. presencesignal has any effect on a pin presence relay 35. The functionsperformed -by this relay will be described later in connection with thedescription of the relay system shown in FIGURE 14.

The A.M. wobble and LM. presence signals are also impressed on thewobble signal channel which :begins with a low pass filter 34, wherehigher frequency components than those encountered in pin wobble areeffectively discriminated against .by this filter. This filter, togetherwith other filtering elements, such as the low pass filter in thephotomultiplier circuit mounted in camera 31, limit the bandpasscharacteristics of the circuit so that the only spurious signals whichcan affect the pin wobble detector, are those with frequency componentssimilar to those produced by pin motion. The effects of long termchanges in illumination for example, are filtered out by couplingcapacitors in the wobble signal channel, while very rapid transients areremoved by the low pass filters. The output of the low pass filter 34 isimpressed on an amplifier 36, and then on a rectifier and limitercircuit 38 the output of which is impressed on a sharp cutoff pentodeamplifier 40. The `output of pentode 40 energizes a relay 42, which hasarmatures 43 and 44. Armature 43 is used for controlling the operationof the pentode, while armature 44 is used for timing the operation ofthe pin-spotter in the manner which will be described later inconnection with the description of the relay system in FIGURE 14. Relay42 will be called the wobble relay because it becomes energized inresponse to pin wobble. As will be pointed out later, the normallyclosed contacts 42a of ten wobble relays are connected in series withthe ma-in relay of the pinspotter and, therefore, the pinspotter relayis energized immediately if there is no wobble or its energization isdelayed as long as any of the ten pins continue to wobble. The verymoment woblble ceases, relay 42 becomes de-energized, the circuit of themain pinspotter relay becomes closed, and the pinspotter is put intooperation. Accordingly, the operation of the pinspotter is controlled bythe wobble relays 42. There is an instant starting when there is nowobble, the length of the delay being controlled by the wobbling pin.

Referring to FIGURE 5, which is the schematic diagram of FIGURE 2 up toand including relay 42, the photomultiplier 50 is the maskedphoto-multiplier, while photo-multiplier 51 is the compensatingphoto-multiplier. The light sensitive photo-cathode 52 receives thewobble and the presence signal and the average illumination signal,while photo-cathode 53 receives only the average illumination signalfurnished by the pinholes 19, 20 and 21 of camera 17. The respectivedynodes of the two photo-multipliers are connected to the respectivecommon resistors 55 through 62. The dynodes 63 and 64 are groundedthrough a grounded conductor 54. The anodes 65 and 66 are connected to apositive source of potential 121 through a conductor 76, fixed anoderesistors 67 and 68 and variable resistors 69 and 70, respectively. Thecathodes 52 and 53 are connected to the negative terminal of a highsource of potential 74, while the positive terminal of this source isgrounded. Condensers 71 and 72 are also connected to the respectiveanodes on one side and to ground on the other side. Condensers 71 and 72act as low pass filters and serve to reduce the cycle per second signalwhich is the modulation signal appearing on the anode due to the doubleline frequency ripple produced by the alley illumination. Thesecondensers also reduce the anode modulation, which in turn reduces thelinear dynamic range required of the difference circuit operated by thephoto-multipliers. The variable resistors 69 and '70 are adjusted, so asto make the two anodes 65 and 66 at the same potential with respect toground when the pinholes in two cameras are open and the pins arestanding on the alley floor.

Since the corresponding dynodes of both photo-multipliers are connectedtogether to the taps on the chain of the common resistors 54 throughv62, some crosstalk signal is produced because of the use of commondynodo resistors; this cross-talk signal is largely cancelled out in thedifference circuit and does not significantly affect the overalloperation of the pin wobble detector. A further reduction in thecross-talk can be obtainted by providing lan independent chain ofresistors for the photo-multiplier 51.

The output of the photo-multiplier 50 is connected through a conductor73 to the grid of a triode 75, while the output of photo-multiplier 51is connected through a conductor 85 to grid 84 of a triode 77. Triodes77 and 75 are conventional cathode follower impedance multiplier stages,and are identified as such by the fact that one terminal of the gridresistance 80 is connected to a tap S2 on the cathode load resistance78-83 through a biasing battery 37. Resistance 78 is a high resistanceas compared to resistance 83. The directl current impedance seen fromgrid 84 to ground is several times the value of the grid resistance 80.The same is also true of grid 86 and its circuit. Moreover, theimpedance multiplying circuit has a Ihigh input impedance and,therefore, does not reduce greatly the photo-multiplier signals byshunting them to ground. The cathode followers 77 and 75 have low outputimpedance and, therefore, long leads 87 and 8S can be run from thecathode followers to the remainder of the cir cuit which is mountedoutside of the camera -box 15. These leads are connected to thedifference circuit 32 which includes a double triode 90 having itscathode connected to a common cathode resistor 41. Grid 92 is connectedthrough conductor 38, resistances 93 and 95 and a biasing battery 96 tothe cathode of triode 77, while grid 96 is coupled to the cathode oftriode 75 through conductor 87, grid resistor 98 and a biasing battery97. Grid 92, therefore, receives only the signal which repre-` sen-tsthe intensity of illumination and variations in the intensity ofillumination due to the voltage fluctuations, while grid 96 receives thesignal proportional to the intensity of illumination, and the variationsin the illumif nation, the wobble signal, and the presence signal. Thedifference circuit, as its name implies, has an output proportional tothe difference of the signals from the two impedance multipliers. Thedifference circuit output is thus proportional to the difference in thetwo signals produced at the two photo-multiplier anodes. When the`intensity of illumination fluctuates, corresponding to a line voltagefluctuation, approximately equal signals are produced at the twophoto-multiplier anodes, and the output of the difference circuit isvery small. When the pin moves, however, the signal produced at theanode 65 of the masked photo-multiplier 50 is very much larger than thatproduced at the compensating photo-multiplier anode. It is also ofdifferent algebraic sign in a random fashion. A detailed description ofthe difference circuit is not necessary because the circuit of this typeis knownl 10 100. When grid 92 -becomes positive, plate 93A becomes morenegative because of the increase in space current and conductor 39 andcondenser 100 receive a negative signal thus subtracting itself from thepositive signal produced by grid 91.

The wobble A.M. signal and the presence LM. signal both appear onconductor 39 and are impressed on condenser 100, which couples thewobble channel to the difference circuit, and on the control grid 151 ofa pentode 150. The wobble channel, through its coupling condenser 100and a low pass filter condenser 105, eliminates the presence signal andtransmits the A.M. wobble signal for energizing the wobble r-elay 42.The presence channel, including pentode 150, shunts to ground the A.M.'wobble signal through a capacitor 152, but the variable level signal,which may be regarded as a direct current signal, is impressed on grid151 making pentode 150 more conducting. This increase in plate currentenergizes the presence relay 35. Relay 35 is shunted by a capacitor 153which improves the operation of relay 35 by decreasing the differencebetween the currents which are necessary to energize and de-energizerelay 35.

Reverting once more to the wobble channel, the wobble signal isimpressed on the control grid of a pentode amplifier 99 throughcapacitor 100 and resistors 103 and 104. [The grid resistor 104 isshunted by a capacitor 105 the value of which is made so as to act as alow pass filter to ground. In one example, resistor 104 had a value of lmegohm, while condenser 105 has a value of 2 microfarads. Higherfrequency components than those encountered in pin wobble areeffectively discriminated against -by this filter. This filter and theother filtered elements, such as condensers 71 and 72, limit thebandpass of the circuit so that the only spurious signals which canaffect the pin wobble detector circuit are those with frequencycomponents similar to those produced by the pin motion. The effects oflong-term changes in illumination and the presence signals, for example,are ltered out by coupling capacitors in the wobble signal -channelwhile very rapid transients are removed by the low pass filtersincluding condensers 71, 72 and 105.

Pentode 99 circuit, which is connected and operates as Class Aamplifier, includes a fixed cathode resistor 106 in series with a gaincontrol potentiometer 107. The output of amplifier 99 is connectedthrough a capacitor 108 to a detector and a limiter circuit including atwin diode 109 and 110. The detector 109 is connected across a resistor111 and in series with a signal storage capacitor 112 so that onlypositive signals impressed on plate 113 make diode 109 conductive and,at the same time, charge up condenser 112 with the upper plate of thecondenser, which is connected to the control grid 114 `of a pentodeamplifier 115, becoming more positive when diode 109 becomes conductive.Therefore, the wobble signals make pentode 115 conductive. The seconddiode 110 acts as a limiter of the positive signal impressed on grid 114because it is connected across condenser 112 through resistors 116 and117 and a conductor 118. The two resistors 116 and 117 act as potentialdivider resistors connected between grounded conductor 120 and a sourceof potential 121. When the voltage impressed on the plate of diodebecomes higher than the voltage impressed `on its cathode by source 121,diode 110 becomes conductive and thus limits the potential that mayappear across condenser 112 and, as a consequence, also limits thepositive signal impressed on grid 114. Because of the limiter 109-110,the time delay between cessation of a very large signal and resumptionof pinspotter operation is no longer than for smaller signals.

The output of limiter 110 is impressed on grid 114 of pentode which hasa circuit to produce sharp cut-olf. Cathode 139 of this pentode isconnected to ground through resistors 134 and 135 and a tap 117 betweenthese resistors is connected over a conductor 136 to the normally closedcontacts 42b of relay 42. The winding of relay 42 is connected in serieswith the plate circuit of pentode 115. The left contact 42b is connecteddirectly to cathode 139 over a conductor 137 and armature 42d is oncontacts 421) when relay 42 is not energized and it opens contacts 42bwhen relay 42 is energized. Therefore, with no wobble signal, thecathode resistor 135 is shunted by armature 42b' resting on contacts42b; shunting of resistor 135 reduces the positive cathode bias oncathode 139 as long as relay 42 is not energized. When relay 42 becomesenergized, the short circuit across resistor 13S is removed and itbecomes connected in series with cathode 139. Therefore, the positivebias on cathode 139 is increased upon energization of relay 42 whichdecreases the magnitude of the grid signal required for de-energizingrelay 42 and also decreases the difference in grid voltage between thelevel at which relay 42 is energized and that at which it isde-energized. The relay winding 42 is shunted by a capacitor 123 foreliminating contact chatter. Condenser 123 is also used for holdingrelay 42 energized if there is a momentary decrease in the wobblesignals below a predetermined level by discharging condenser 122 throughwinding 120. Conductor 66 connects relay 42 to the positive terminal ofsource 121. Conductor 66 is also connected to conductor 136 through aresistor 131 for obtaining proper bias of pentode 115. A wobble signal,impressed on grid 144 is a positive signal and, therefore, it causes anincrease in the space current, which causes a current increase throughwinding 42 and if this increase in current is sufficiently large, relay42 will lbecome energized. Normally tube 115 is non-conductive sincegrid 114 is at ground potential and cathode 133 is at some positivepotential determined by the values of the resistors 134 and 131 whichare connected across the power supply 121. Therefore, grid 114 is at anegative potential with respect to cathode 133.

The wobble relay 42 controls the time of closing of the pinspotter mainrelay 302 since contacts 42a and conductors 155 and 156 are connected inseries with the main pinspotter relay, as will be described later inconnection with the description of FIGURE 14.

Impedance pin wobble and pin presence detector The impedance type pinwobble detector belongs to the class of pin wobble detectors whichrequires the use of sensors or detectors, in the alley oor. An impedancepin wobble and pin presence detector involves the measurement of thechange in the impedance of a circuit. Looking into the sensors in thealley floor, such change in the impedance may be produced by usingcapacitors or inductance coils as sensing devices. The sensing systemusing inductance coils is -more sensitive than that using the capacitorsand will be described first and it will be followed with the descriptionof the capacitive system.

In the inductance system, the pin wobble and pin presence signals areproduced by a continuous measurement of the change in the coeflicient ofcoupling between a coil mounted in the alley oor and a coil mounted inthe base of a pin, and loading of the floor coil by the pin coil. Inorder to make this system as sensitive as possible, the two coils shouldbe placed as closely as possible to each other. The floor coils and thecoil in the base of the pin, nevertheless, should be recessedsufficiently so as to permit the insertion of an insulating layer ofsufficient thickness which would protect the coils from ordinary wearand tear. The insulating material suitable for this purpose is thePermabase plastics material described in the U.S. Patents 2,739,814 and2,680,023. A floor coil may consist of a suitable number of turns ofwire with a capacitor connected across this coil to tune the circuit tothe operating frequency with the pin removed from the alley floor.Although the frequency range of such system is not critical, the ultrahigh frequency (UHF) and the high frequency range is less desirablebecause the losses in the surrounding medium at these higher frequenciesare larger than at the lower frequencies. On the other hand, the audiofrequencies would require large coils, which are not suitable from thepractical point of view. Accordingly, the range of frequencies which ismost suitable for the systems of the above type is between kilocyclesand 2 megacycles.

When the pin is placed on the floor coil, connected to a source ofcarrier frequency, and wobbled, a modulated carrier signal is produced.The modulated carrier signal acts as an indication of pin wobble.Moreover, an increase in the amplitude of the carrier (level modulation,mentioned previously) is produced when the pin is removed or knockedover because of the decrease in the losses produced in the floor coil bythe pin coil. Accordingly, the amplitude modulated signal, and change inthe level of the carrier signal, may be used for obtaining an indicationof pin wobble and pin presence, respectively. The wobble signal isobtained by detecting its amplitude modulation. The same detector canalso be used to produce the carrier level output signal, which is thedirect current output, for indicating the presence of any individualpin. A block diagram of such system is illustrated in FIGURE 7. Thecircuits used in the inductance pin wobble and pin presence detector areknown in the art and, therefore, no schematic diagram of the circuits isnecessary. However, suitable specific circuits will be mentioned in thecourse of the description of the block diagram, to identify the types ofcircuits which are capable of performing the intended functions in theoptimum manner.

Referring to FIGURE 6, a coil 600, or an electronically equivalentelement, is the coil installed in the base of a standard pin. Maximumuseful signal is obtained if the pin coil is tuned to the frequency ofthe applied voltage. The output signal may be increased, for example,ten times since it is relatively easy to make Q, or the figure of merit,of the coil equal to at least ten. The pin coil may consist of enoughturns of wire to tune it with the aid of a condenser 601 connectedacross the coil to the frequency of the oscillator used for producingthe carrier frequency. Since each inductance coil has its own resonancefrequency, it is also possible to use only a coil 600 without any use ofcondenser 601 so long as the coil is made resonant at the carrierfrequency. Bowling pins of this type, provided with a single coil, or aplurality of turns and the electronically equivalent elements, aredisclosed more fully in the previously mentioned Patent No. 2,973,206 ofMilton Sanders, which is made a part of this disclosure. The floor coil602 and the condenser 603 are tuned to the same carrier frequency andthe tuned circuit 602-603 is connected to a cathode follower 604 througha resistor 60S and a condenser 606. With the impedance looking into thetuned circuit from the cathode follower 604 being made equal to theoutput impedance of the cathode follower, a fifty percent change in theoutput voltage may be obtained in the output signal appearing on aconductor 607 when the pin coil is removed, i.e., when the pin isknocked over. It should be stated here that ten identical channels, onechannel for each pin, are required with the system disclosed in FIGURE6, only two channels being illustrated in the figure. A singleoscillator 608, such as a tuned grid oscillator, is used for impressingthe carrier frequency on the ten tuned circuits. It is preferable tohave a crystal controlled oscillator to avoid frequency drifts and theloss in the sensitivity of the circuits due to such frequency drifts.Oscillator 608 is isolated from the tuned circuits by interposing anamplifier 609 and a buffer amplifier, or a cathode follower, 610. Thebuffer amplifier 610 is connected to ten cathode followers 604 over aconductor 660 with each cathode follower 604 being connected to therespective floor coils 602. Oscillator 608 thus furnishes the carrierfrequency to the ten tuned circuits. The output of the tuned circuits isconnected over conductor 607 to a detector 611. The direct currentoutput of detector 611 is connected over a conductor 612 to a directcurrent presence amplifier 613. The signal impressed on amplifier 613represents the average level of the signal appearing in the output ofdetector 61E.. This average level is constant when there is no wobbleand its level is modulated when there is a wobble. It increases greatlywhen the pin is absent.

The direct current presence signal (the previously mentioned levelmodulation signal) is impressed on a presence amplifier 613 through ametallic, direct current path by connecting the plate of detector 611 tothe grid of the presence amplifier 613, the plate resistor of thedetector also acting in such case as a grid resistor for the grid of thepresence amplifier 613. Amplifier 613 corresponds to the amplifier 33 inFIGURE 2 and pentode 150 in FIGURE and performs the same function as theabove elements in FIGURES 2 and 5. The output of the presence amplifier6l3 is connected to the presence relay 35 corresponding to theidentically numbered relay in FIG- URES 2 and 5. The operation and thecontrol functions performed by relay 35 will be described later inconnection with the description of FIGURE 14.

T he output of detector 6M is impressed on a wobble amplifier 621 whichcorresponds to the wobble amplifier Q9 in FIGURE 5 and amplifier 36 inFIGURE 2. A low pass filter 34 may also be included in the wobblechannel. In general, the wobble channel in this detection system isidentical to the wobble channel 34, 36, 38, 40 and 42 of FIGURE 2, andthe same channel shown in schematic form in FIGURE 5. Condenser 622 inFIGURE 6, therefore, corresponds to condenser 100 in FIGURE 5. Thewobble relay 42 in FIGURE 5 therefore, performs the same function as thewobble relay 42 in the prior figures.

One of the advantages of the system disclosed in FIGURE 6 is that ituses only one oscillator 608 for producing a carrier frequency for allten channels. At the same time, the use of one oscillator requires acareful tuning of the floor and pin coils 602 and 600 and capacitors 603and 601. The system disclosed in FIGURE 6 performs well once the tunedcircuits in the pin and in the floor are properly adjusted. Oneadditional factor which one should take into consideration in connectionwith FIGURE 6 is that the length of the cable between the tuned circuit602-603 and the cathode follower 604 causes the effective Q, or thefigure of merit, of the fioor coil to be lower than the measured Q ofcoil 602.

The operating characteristics of the system disclosed i-n FIGURE 6 maybe improved by providing ten separate oscillators with the iioor coilsthemselves being the frequency determining elements by making t-hesecoils as an integral part of the oscillator with the oscillator anddetector mounted in the center of the floor coil form. In this mannerthe length of the cable between the oscillatordetector and the coil isreduced to zero. Moreover, such construction is lcapable 0f increasingthe signal level enough to make the precise tuning of the pin coilsunnecessary.

The system of the above type is illustrated in FIGURES 7 and 8. FIGURE 7illustrates a block diagram of the circuit, while FIGURE 8 illustratesthe schematic diagram of a suitable oscillating detector circuit whichcan be used for producing the individual carrier frequency signal anddetection of this signal in each individual channel. The performance ofthe system disclosed in FIG- URE 7 is superior to the performance of thesystem disclosed in FIGURE 6, but it requires the placement of theoscillator detector circuit in the center of the fioor coil form andrequires ten oscillator-detectors. This disadvantage, however, is morethan compensated by the superior performance of the system.

Referring to FIGURE 7, the pin coil-capacitor combination is coupled, asbefore, to the licor coil-capacitor combination 701 and the latter isconnected to the oscillating detector circuit 702. The output of theoscillating detector is impressed on a conductor 703 to indicate thepresence of the particular pin While the wobble signal appears onconductors 704 `and 705 Iwhich are connected to each other through acapacitor 706. Identical elements are used in each channel for each pinand, therefore,` there are ten channels altogether. A grounded resistor707 is used as a grid leak and also as an output impedance of theoscillating detector circuit illustrated in schematic form in FIGURE 8.Conductors 703 are connected to the individual presence amplifiers, suchas amplifier 613 in FIGURE 6, and amplifier 150 in FIGURE 5, and thewobble signal, appearing on conductor 705, is impressed on the wobblesignal channel identical to that shown in FIGURES 2 and 5. Conductor 705yand capacitor 706, therefore, correspond to conductor 45 and capacitorl0() in FIGURE 5. The relay system operated by the detector circuits ofFIGURE 7 is identical to the relay system of the prior gures and thatdisclosed in FIG- URE 14.

FIGURE 8 discloses the circuit of the oscillating detector which can beused in block 702 of FIGURE 7. The oscillator is the Hartley oscillator.The pin coil 820 (with or without a condenser S21) is -coupled `asclosely -as practicable from the point of view of wear and tear to thefloor coil S22 which has a tap 823 connected to the cathode of triode824. Coil 822 is :shunted by la condenser 825. The tuned circuit S22-S25is coupled to the grid by `a capacitor 826. The grid is also connectedto ground through -a resistor 827. The presence and the wobble signalsare impressed over a conductor 828 on the presence channel similar tothat disclosed previously, and the wobble signals are impressed throughIcapacitor on conductor 45 which correspond to the identically numberedelements in the prior figures. When the pin coil is in the proximity ofthe floor coil 322, the overall Q of the tuned circuit is not as high aswhen coil 820 is absent. Accordingly, with the pin standing, theamplitude of the oscillator is not as high as with the pin absent and,therefore, the amplitude of the alternating signal appearing acrossresistor 827 is not as high with the pin standing as it is with the pinabsent. When the pin is absent, the detector oscillator develops a largenegative grid voltage appearing across resistor 827 and this signal isimpressed on the outgoing presence channel. The wobble channel filters.out such signals, through the coupling lcondensers and the low passfilters described previously and, therefore, the operation of the wobbleamplifier 99, FIGURE 5, is not affected by the presence signals.

The circuits disclosed in FIGURES 7 and 8 are thus capable of detectingthe wobble and presence of the pins, and furnish two distinct signals,the amplitude modulation wobble signal and the level modulation presencesignal, which can be separated in the electronic channels and thendirected to the relay circuits of the type illustrated in FIGURE 14 forcontrolling the operation of the pinspotter in the manner which will bedescribed in connection with FIGURE 14.

FIGURES 9 through i3 disclose additional versions of the inductance andcapacitance pin wobble and pin presence detectors which use a Wheatstonebridge for detecting the wobble and presence signals produced by theindividual pins. FIGURE 9 is a block diagram for such systems. The baseof pin 901 is provided with a coil or a coil-condenser combination ifthe Wheatstone bridge 902-903 is an inductance bridge. If the bridge isa capacitive bridge, the pin itself acts as a capacitive element and,therefore, conventional pins may be used without the insertion of anyadditional elements in the base of the pin. The bridge circuit isconnected either to a local oscillator or an oscillating detector of thetype shown in FIGURE 8. The output of the bridge is connected to anamplifier 904 which impresses its output on conductor 39 condenser 100and conductor 45 corresponding to the identically numbered conductors inprior systems. Ten

individual channels are required for continuously detecting the statusof ten pins, one channel for each pin.

FIGURES and 1l illustrate the inductance system using inductance coils1000 in the alley oor and an inductive ring 1002 or a coil or permeableinsert at the bottom portion of pin 1003. In all cases the bridges areconnected to a carrier source 1005 whose frequency may bein the range of50,000 cycles per second and 2 megacycles per second as describedpreviously.

FIGURES 12 and 13 illustrate a capacitive bridge detector, ortransducer; in such transducer, metallic plates 1200 and 1201 aremounted in the floor of the alley in the manner illustrated in FIGURES12 and 13 to form individual capacitors. In such case a pin 1300 may bea conventional pin with or without any metallic inserts in its bottomportion; the bottom portion can also be made of the plastics compositionknown as Permabase, mentioned previously. In either case, wobble orabsence of the pin produces an unbalance in the inductance or capacitivebridges and this signal or signals are used for controlling thepinspotter in the manner described below.

In summarizing the systems using an impedance bridge, the inductivesystems require that a mass of permeable material, such as anelectrically conducting ring or a coil, be placed in the pin bottom. Ineither case, motion of the pin changes the inductance of the coil placedin the floor, under the pin, and this change of inductance can bemeasured by using an alternating current bridge whose output isamplified and used to control the pinspotter cycle. Such transducerfurnishes the presence and the wobble signals coil inductance ismeasured continuously. The absence of a pin causes a reduction in theamplitude of the signal, while a wobbling pin produces a modulatedsignal. The two types of signals are separated in the manner describedpreviously in the two channels. The knocked-over pins will produce onlya very small inductance change when rolling or spinning on the floorand, therefore, the systems of this type can be made to interrupt thepinspotter cycle when pins are wobbling without responding to therolling or spinning pins.

The same is also true of the system using a capacitance bridgeillustrated in FIGURE 12.

Relay system for Controlling the operation of pinsetting machine Therelay system for controlling the operation of a pinsetting machine isdisclosed in FIGURE 14. The disclosed relay system comprises theapplication of the pin wobble and pin presence detection system to thebowling pinsetting machines of the type disclosed in the U.S. patent,No. 2,559,274 dated July 3, 1951, which is made a part of thisdisclosure. There are now in use throughout the United States laterversions of the machine distributed by the American Machine & FoundryCompany, the assignee of the above patent and of this application. Theteachings of this invention are also applicable to the machines now inactual use which, for example, are described, in part, in ProductEngineering, .lune 1954 issue, and Roger E. Dumas application forpatent, S.N. 226,359, tiled May 15, 1951, now Patent No. 2,821,395, thelatter being also incorporated by reference as a part of thisdisclosure.

Since this invention uses several phases of the functional cycle of themachine disclosed in the U.S. patent, No. 2,559,274, it is unnecessaryto disclose here the overall structure of the machine; such structure isfully disclosed in the above patent and a more recent U.S. patent, No.2,773,689, granted December 11, 1956. The same is also true of the relaysystem disclosed in FIGURE 4 of the patent, No. 2,559,274, whichdiscloses the overall relay system for controlling the operation of theentire machine. Accordingly, FIGURE 14 in this application illustratesonly the modifications in the relay system disclosed in FIGURE 4 of thepatent, N0. 2,559,274, and the remaining elements of the overall relaysystem are omitted altogether. However, the functioning of the entirerelay system will be apparent to those skilled in the art from thedescription of the modifications in the relay system appearing inpatent, No. 2,559,274. In order to facilitate the understanding of thedescription of the relay system, and its relationship to FIGURE 4 inPatent No. 2,559,274, those elements of the relay system of FIG- URE 4of the patent, which are also shown in FIGURE 14, bear the sameidentifying numerals as those used in the patent and such elements, fora more ready identification are put in quotation marks. For example, thepit switch 300 indicates that it is identical to the identicallynumbered switch 300 in FIGURE 4 of the patent.

Wobble system The operation of the wobble detecting systems has beendescribed previously. It also has been stated previously that the wobblerelay contacts 42a normally are closed and become open only when relays42 receive wobble signals. Accordingly, these relays can control thestarting time of the entire machine by connecting these ten wobblerelays in series with the main relay 302 and the pit switch 300 in themanner indicated in FIG- URE 14. A source of potential 1400 is connectedin series with conductors 391, 301a, wobble relay contacts 42a and theWinding of relay 302. The circuit of the main relay 302 is as follows.Grounded source 1400, pit switch 300, contacts 300a of pit switch 300,conductor 301e, normally closed contacts 42a of ten wobble relays421-4210, conductor 391, and grounded winding of relay 302; which closesthe entire circuit through the grounded terminal of source 1400. The pitswitch becomes closed immediately after it is struck by a ball;therefore, after switch 300 closes, the energization ofthe above circuitis controlled only by the ten serially-connected wobble relays 42.Accordingly, the entire cycle of the pinsetter is now controlled notonly by the closing of the pit switch 300, as disclosed in the abovepatent, but also by the ten wobble relays 421-4210, any one of which iscapable of delaying the operation of the machine until the wobbleceases, whereupon the affected relays 42 become de-energized, contacts42a become closed, and the operation of the machine takes place the verylmoment the wobble ceases. Relay 302, therefore, is a fast-acting relayas differentiated from the delayed closing relay 302 in the abovepatent. Once the relays 42 are all closed, when all wobble ceases, themachine is allowed to operate without any other delay. When there is nowobble, the machine is permitted to operate immediately after the -ballstrikes pit switch 300 and the fast-acting relay 302 is energized. Theoperation of the machine, from then on, is identical to that disclosedin the above patent with the modications which are pointed out below,and which are caused by the prevention of its normal operation:

(l) Whenl the lirst ball is a lgutter ball; when the iirst ball as wellas the second ball are both gutter balls;

(2) When only pin #7 or pin #10 is knocked down by the first ball, andall other pins are standing.

From the above description of the wobble relay circuit,

From the above description of the wobble relay circuit, it follows thatthe initial starting of the machine is now controlled by the pit switch300 as well as ten wobble relays 42. There is an instantaneous startingof the machine when there is no wobble after the first or the secondball or any other ball, and a variable delay starting if there is awobble, in which case the machine is started immediately after thewobble ceases.

Pin presence system The pin presence signal is impressed on a directcurrent amplifier 33, FIGURE 2, and then a pin presence relay 35, whichis provided with three sets of contacts 35a through 35C all mounted on arelay armature 35d. The normal position of this armature, correspondingto the bowling pin standing on the alley floor, is that illustrated inFIGURES 2, 5, 6 and 14. Contacts 35a are open and contacts 35b and 35Care normally closed with the exception of contacts 35b on relays 351 and3510, which are normally open and are connected in parallel by means ofconductor 1401 and 1402. All the remaining contacts 35b are normallyclosed with the pins standing and are connected in series with eachother and conductors 1401 and 1402. Conductor 1403 is grounded andconductor 1404 is connected to cam-operated contacts 35d and 35e whichare closed and opened by a cam 35 having the contact-closing portion1405 extending over approximately l60-170 of the cam 35f. Cam 35f iskeyed to a shaft 255 corresponding to the similarly numbered shaft inthe patent. It is the electrical control cam shaft on which allelectrical control cams are mounted, as described in col. 8, lines 62-75and col. 9, lines 1 and 2 of Patent No. 2,559,274. As stated in theabove description, the control cam shaft 255 makes only one revolutionfor every two revolutions of the main cam shaft 28 and is driven byshaft 2S. The control cam shaft 255 makes one revolution for every twoballs, and one half of a revolution for the first ball and the remainingone half revolution for `the second ball. Contacts 35b of the presencerelays 35 are those sets of contacts which are used for eliminating theoperation of the pinsetting machine when only pin #7 or pin are knockedout by the first ball and all other pins remain standing. As mentionedpreviously, it is unnecessary to lower the table and reset the pinsunder the above conditions since the remaining pins are standing inproper manner and positions and, therefore, are immediately ready forrolling the second ball. The series circuit which controls the operationof the machine under the above conditions is grounded source 1400,conductor 1405, winding 1406 of' the relay having two sets of contacts1406a and 1406b, conductor 1407, contacts 35e and 35d, which are closedduring the first ball play, conductor 1404, closed contacts 35h andgrounded conductor 1403. Contacts 35h remain closed as long as pins 1through 6, 0 and 9 are standing and contacts 35111 or 35h10 becomeimmediately closed if either pin #7 or pin #l0 is knocked down by thefirst ball. Closing of contacts 35191 or 35b10 completes the circuit andthis energizes relay 1406. When relay 1406 becomes energized, contacts1406a open which prevents energization of the clutch relays 360 and 1408which prevents the lowering of the table. Relay 360 corresponds to thesimilarly numbered relay in Patent No. 2,559,274 and, as described inthe above patent, it is used for actuating clutch Ii-4. This preventsengagement of the clutch 1K-4, and thereby prevents the setting of newpins but allows the machine to operate and return the ball to theplayer. The functioning of clutch X44 per se in the machine disclosedhere is identical to the functioning of clutch Ii-4 in the patent. Thedifference resides in the interposition of relay 1406 which prevents theactuation of relay 360 when only pin #7 or pin #10 is knocked out on thefirst ball and when the first ball is a gutter ball and the second ballis also a gutter ball. The circuits of all clutch relays, such as K-1,K-Z and K-3, are identical to the circuits in the patent and, therefore,need no description. The circuit of clutch K-4 differs only in onerespect; i.e., an additional control relay 1406 has been connected inseries with the following circuit: a grounded source 1410, conductors1411, 1412, contacts 361e of relay 361 conductor 1413, contacts 1406a,conductor 1414 and grounded winding 360. With the exception of relay1406 and contacts 1406a, this circuit is identical to that in the patentand normally performs the same function as long as contacts 1406::remain closed. The circuitry and the functions performed by relay 361remain the same as those in the patent.

Reve-rting once more to the electrical control cam 13 shaft 255 andcontacts 35e and 35d, it is necessary to include these cam-operatedcontacts in the circuit of relay 1406 because this relay should beoperated by the closing of the contacts 35b10 or 35b1 only after the rstball of a frame has been rolled. Shaft 255 and cam 35,1c opencontacts35e35d after the rolling of the second ball and thus permit the normaloperation of the machine after the second ball even if only pin #7 orpin #10 are knocked down by the second ball and all the remaining pinsare standing.

Gutter balls.-It has been stated previously that the disclosed relaysystem prevents needless operation of the machine when the first ball isa gutter ball and when the lfirst and the second balls are both gutterballs. The above is accomplished with the aid of the presence relays,their second set of contacts and two gutter switches which also controlthe operation of relay 1406 in the manner described below.

The second set of contacts of the presence relays 351- 3510 are contacts35C. All contacts 35e are normally closed as long as the pins arestanding, and are connected in series with` source 1400, conductor 1405,winding 1406, conductor 1414, contacts 35C, and two gutter ball switches1415 and 1416-, which lare connected in series with contacts 35e and inparallel with respect to each other. Source 1400 supplies power to relay1406 and energizes it when either the iirst ball or the first and thesecond balls are gutter balls. Accordingly, contacts 35C and gutterswitches 1415 and 1416 control the operation of relay 1406 which isnormally de-energized because of the normally open position of the twogutter ball switches 1415 and 1416. Operation of clutch K-4, therefore,is also prevented when the first ball is a gutter ball and when thefirst and the second balls are gutter balls.

FIGURES l5 and 16 illustrate the type of gutter ball switches 1415 and1416 which are suitable for performing the function assigned `to them bythe `relay system. FIG. 15 illustrates the positioning of the switchesat the irnner ends 1500 and 1501 of the two gutters 1502 and 1503. Theswitches include collars 1504 and 1505 which are supported in anelevated position above the gutters by springs 1507 mounted in dash-pots1506. The dashpots, fitted with suitable uid, furnish suicient timedelay to maintain the contacts 1415 closed for that period of time whichis required for preventing energization of clutch K-4 after the gutterball strikes pit switch 300 and puts the relay system into operation forone cycle of operation required either after the first or the secondballs of a frame.

From the description of the gutter ball circuits, it follows that it ismade operative only if all the pin-s remain standing, all relays351-3510 remain de-energized, and all contacts 35e remain closed.Opening of any contacts 35C, which takes place if any of the pins areknocked down, makes the gutter ball circuit ineffective, contacts 1406aremain closed, and the machine is allowed to operate in its usualmanner, as described in Patent No. 2,559,274.

A single Irelay 1406 is used for controlling the operation of clut-chK-4 by the gutter ball circuit described above and also by the #7 or #10pin circuit described previously. The two circuits are in parallel witheach other and have independent contacts 35b and 35C on the presencerelays 35. The gutter ball circuit is not affected by the operation ofcam 35]c and contacts 35e and 35d.

Clutch K-5.-In the cycle of the pinsetting machine disclosed in Patent2,559,274, the operation of the pin carrying grippers 68 of the transferdevice N are moved by cam 128 back and forth once each cycle of themachine, as described in col. 10, lines 44-54. As also described in col.7, lines 26-40 of the patent, the movement of table T to and from thepin supporting bed of the alley for setting and/ or resetting pins isalso effected by means of a cam 148 which is formed integrally with cam128, both of these cams being mounted on a cam shaft 28. In order topreselye the function of these two cams in the normal operation of themachine described in the patent and also adapt their functioning to themodilied cycle disclosed here, an additional clutch K-S has been mountedon shaft 28. This clutch, and its solenoid winding 1408, are identicalto clutch K-4. The circuit of solenoid 1408 is identical to the circuitof solenoid 360 of clutch K-4, the two solenoids being connected inparallel to conductor 1414. Therefore, the two solenoids are operated atthe same time and under the same conditions which produce theenergization of solenoid 360. In view of the above, clutch K-4 may beused for not only clutching and declutching cam 74 to and from shaft 28,but also for clutching and declutching cams 128 and 148 to and from thesame shaft. Accordingly, the operation of the pin grippers 68 and themovement of table T is now also under control of the gutter ball circuitand #7 or #10 pin circuit; i.e., it is under control of the presencerelays 351-3510 and gutter switches 1415 and 1416.

Pnfall signalling The presence relays S51-3510 and their contacts 35aare also used for operating the pinfall signalling lights 1 through 10,FIGURE 14, corresponding to the pin positions 1 through 10. In PatentNo. 2,559,274, the pinfall signal lights are operated by means ofrespotting cups 112 which are provided with the switch actuating members320 which are raised in respotting cups 112 and close contacts 321 andcircuit 322-324. Closing of circuit 322-324 energizes relay 326 whichcloses contacts 326a, 326b and 326C. The closing of contacts 326a lightsa signal lamp (1-10) corresponding to the position of the particular pinwhich remained standing. The pinfall signal relays 326 remain locked infor the remainder of the cycle, after which the light circuits arebroken by the de-energization of relays 326 through the opening of camcontact 362a (not shown in FIGURE 14 but shown in FIGURE 4 of thepatent) mounted on shaft 255. De-energization of relays 326 extinguishesthe pinfall signalling lights thus completing the pinfall signallingcycle for any given ball.

In the disclosed system, the information about the presence or absenceof the pins is furnished by the presence relays 35 immediately after anyparticular pin is knocked down. When a pin is knocked down, the presencerelay 35 corresponding to the knocked down pin becomes energized andcontacts 35a, corresponding to contacts 323 in the patent, become closeand the corresponding relay 326 becomes energized. From then on, theoperation of the pinfall signalling means described here is identical tothat in the patent. Accordingly, while in the patent the pinfallsignalling mechanism is operated by the respotting cup 112, in this casethe pinfall signalling mechanism is operated by the presence relays 35directly. Therefore, the respotting cups 112 need not have any switches320-323 according to this invention since they are replaced by thecontacts 35a and armatures 35d of the presence relays 35.

Contacts 1406b of relay 1406 From the prior description of the functionsperformed by relay 38, it follows that relay 38 prevents the operationof clutch K-4 when (a) only pin #7 or pin #10 is knocked down by thefirst ball, and (b) when the rst ball is a gutter ball and when bothballs are gutter balls. Since clutch K-4, when energized, connects cam74 to shaft 28, cam 74 remains inoperative and frame M and table Tremain stationary as long as clutch K-4 remains de-energized. Therefore,switch 298 also remains in its open position because switch 298 isclosed by cam 168 only when the table reaches its lowermost orpin-engaging position because switch 298 is closed by cam 168 only Inorder to preserve the normal functions of the machine, even whenoperation of clutch K-4 and lowering of table 20 T does not take placebecause of the operation of relay 1406, relay 1406 is provided withcontacts 1406b which close when relay 1406 becomes energized and by-passswitch 298.

What is claimed as new is:

1. In a control mechanism for an automatic bowling pin-setting machine,the combination of a detection system comprising a transducer for eachpin of a set of ten bowling pins, said transducers each having means forproducing an electrical signal in response to knocking down of itsrespective bowling pin, ten presence signal channels each connected to adifferent one of said transducers, ten presence relays each connected onthe output side of a different one of said presence signal channels torespond to signals provided from the corresponding one of saidtransducers via such channel, each of said presence relays having a setof normally closed gutter ball contacts and all of said gutter ballcontacts being connected in series with each other, two normally opengutter ball switches each adapted to be positioned at the end of adifferent one of the gutters of the alley so as to be actuated to closedposition when a bowling ball rolls along the gutter and over the gutterball switch, said gutter ball switches being connected in parallel witheach other and in series with said gutter ball contacts of said presencerelays; a main cam shaft, a solenoid-actuated clutch mounted on saidshaft and adapted to control the operation of a pin-setting mechanism ofthe machine with which the control mechanism is to be associated, anenergizing circuit connected to the solenoid of said clutch forsupplying current to said solenoid to energize the same, a control relayhaving an energizing winding and a set of normally closed contacts, thenormally closed contacts of said control relay being connected in saidenergizing circuit in series with said solenoid, the energizing windingof said control relay being connected in series with the gutter ballcontacts of said presence relays and also in series with said gutterball switches, said gutter ball switches, upon closing, energizing saidcontrol relay to cause said set of normally closed contacts thereof toopen for preventing energization of said solenoid of said clutch andthereby prevent operation of the pin-setting mechanism controlledthereby when the first ball in a frame is a gutter ball and also whenthe rst and second ball in a frame are both gutter balls.

2. In a control mchanism for an automatic bowling pin-setting machine,the combination of a bowling pinrespotting table movable between a lirstposition clear of the bowling pins, and a second position to respotstanding pins during a respotting cycle of operation; an operatingmechanism to operate said respotting table to said first and secondpositions during a respotting cycle; detecting means to detect aknocked-down pin of any of a set of ten bolwling pins at the usualten-pin spots of a bowling alley, said detecting means operating toconstantly monitor standing pins at least prior to any movement of therespotting table after a ball is played; control means connected betweensaid detecting means and said operating mechanism and controlling saidoperating mechanism to complete a respotting cycle, after a first ballof a frame is played, in response to sensing by said detecting means ofthe knocking down of a bowling pin at any of pin spots 1-6, 8 and 9;said control means including means immediately responsive to detectionby said detecting means of the knocking down of only the pin at spot 7the pin at spot 10, to prevent the occurrence of any motion of saidrespotting table and to eliminate a respotting cycle of operation ofsaid respotting table; whereby said respotting table remains motionlessin said rst position and a respotting cycle is eliminated if only` saidspot 7 pin or spot 10 pin is knocked down.

3. In a control mechanism for an automatic bowling; pin-setting machine,the combination of a detection system comprising transducer meansconstantlyl monitoring each pin of a set of ten bowling pins at leastduring the interval when a played ball passes through the pin area,

each said transducer means having means for producing an electricalsignal in response to knocking down of its respective bowling pin, tenpresence signal channels each connected to a different one of saidtransducer means; ten presence relays each connected on the output sideof a different one of said presence signal channels to respond tosignals provided from the corresponding one of said transducer means viasuch channel, the ones of said presence relays connected to the presencechannels and transducer means for the pins of the set corresponding topin positions 1-6, 8 and 9 having a normally closed set of contacts, theother two of said presence relays having a normally open set ofcontacts, said normally open sets of contacts being connected inparallel with each other, said normally closed sets of contacts beingconnected in series 'with each other and with the panallel combinationof said normally open sets of contacts, a control relay having anenergizing winding and a set of normally closed contacts, the winding ofsaid control relay being connected in series with said sets of contactsof said presence relays, said pin setting mechanism including a bowlingpin respotting table having a normal position clear of standing pins onthe alley, an electrically operated mechanism energizable to operatesaid respotting table and move same from its normal position through arespotting cycle, said normally closed contacts of said control relaybeing connected in series with said electrically operated mechanism toprevent said mechanism from being energized and hence prevent anymovement of said respotting table from its normal position when saidcontrol relay is energized; detection by the transducer means of theknocking down of only the pin at pin posit-ion 7 or the pin at pinposition 10 by the rst ball of a frame causing immediate energization ofthe corresponding one of said presence relays with resultantenergization of the winding of said control relay, whereby saidrespotting ytable remains motionless in its normal position when onlythe pin at pin position 7 or the pin at pin position 10 has been knockeddown with the other pins remaining standing.

References Cited bythe Examiner UNITED STATES PATENTS 2,628,098 2/ 1953Bauerschmidt 273--43 2,697,605 12/ 1954 Montooth et al. 273-43 2,773,68912/ 1956 Patterson et al. 273--43 DELBERT B. LOWE, Primary Examiner.

2. IN A CONTROL MECHANISM FOR AN AUTOMATIC BOWLING PIN-SETTING MACHINE,THE COMBINATION OF A BOWLING PINRESPOTTING TABLE MOVEABLE BETWEEN AFIRST POSITION CLEAR OF THE BOWLING PINS, AND A SECOND POSITION TORESPOT STANDING PINS DURING A RESPOTTING CYCLE OF OPERATION; ANOPERATING MECHANISM TO OPERATE SAID RESPOTTING TABLE TO SAID FIRST ANDSECOND POSITIONS DURING A RESPOTTING CYCLE; DETECTING MEANS TO DETECT AKNOCKED-DOWN PIN OF ANY OF A SET OF TEN BOWLING PINS AT THE USUALTEN-PIN SPOTS OF A BOWLING ALLEY, SAID DETECTING MEANS OPERATING TOCONSTANTALLY MONITOR STANDING PINS AT LEAST PRIOR TO ANY MOVEMENT OF THERESPOTTING TABLE AFTER A BALL IS PLAYED; CONTROL MEANS CONNECTED BETWEENSAID DETECTING MEANS AND SAID OPERATING MECHANISM AND CONTROLLING SAIDOPERATING MECHANISM TO COMPLETE A RESPOTTING CYCLE, AFTER A FIRST BALLOF A FRAME IS PALYED, IN RESPONSE TO SENSING BY SAID DETECTING MEANS OFTHE KNOCKING DOWN OF A BOWLING PIN AT ANY OF PIN SPOTS 1-6, 8 AND 9;SAID CONTROL MEANS INCLUDING MEANS IMMEDIATELY RESPONSIVE TO DETECTIONBY SAID DETECTING MEANS OF THE KNOCKING DOWN OF ONLY THE PIN AT SPOT 7THE PIN AT SPOT 10, TO PREVENT THE OCCURRENCE OF ANY MOTION OF SAIDRESPOTTING TABLE AND TO ELEMINATE A RESPOTTING CYCLE OF OPERATION OFSAID RESPOTTING TABLE; WHEREBY SAID RESPOTTING TABLE REMAINS MOTIONLESSIN SAID FIRST POSITION AND A RESPOTTING CYCLE IS ELIMINATED IF ONLY SAIDSPOT 7 PIN OR SPOT 10 PIN IS KNOCKED DOWN.